Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 14 de 14
Filter
1.
Med Sci Monit ; 30: e944692, 2024 Jul 15.
Article in English | MEDLINE | ID: mdl-39004882

ABSTRACT

BACKGROUND Digital dental (DD) technologies need to be developed for dental use because of the prominent position that these technologies have recently acquired. This 21-item online questionnaire-based study aimed to assess the understanding of DD methods in 120 undergraduate dental students at King Faisal University, Saudi Arabia (SA). MATERIAL AND METHODS Electronic surveys were sent to 123 dental students at different study phases (basic, preclinical, and clinical). Dental students were requested to answer the questionnaires in accordance with their knowledge, observations, particular experiences, and DD practice. Data were analyzed using descriptive statistics, which involved numerical values and ratios. Then, the associations among study level, knowledge, practice, and study phases were analyzed using chi-square and Fisher's exact tests. RESULTS Completed questionnaires were returned by 120 students. The chi-square test showed significant differences in relation to questions "Do you have any previous knowledge of DD?", "The field that uses DD the most is…", "Does DD provide more precise results than conventional dentistry?", and "Do you know about CAD/CAM?", with P values of 0.006, 0.000, 0.018, and 0.002, respectively. Students at clinical phase exhibited significantly higher levels of knowledge than those at the preclinical phase (P<0.01). With regard to DD practice, 73.3% of students expressed a negative viewpoint, 82.5% stated that DD is essential for the future, and half said that practicing DD will result in improvements in patient satisfaction, time consumed, and level of predictability. CONCLUSIONS Students at basic, preclinical, and clinical phases had good knowledge on DD and were motivated to practice it in future in their workplaces.


Subject(s)
Students, Dental , Saudi Arabia , Students, Dental/statistics & numerical data , Humans , Surveys and Questionnaires , Male , Female , Education, Dental/methods , Universities , Dentistry/methods , Health Knowledge, Attitudes, Practice , Adult , Young Adult , Digital Technology
2.
Cureus ; 16(1): e53229, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38425593

ABSTRACT

BACKGROUND: Asthma is a major non-communicable disease affecting both children and adults and is the most common chronic disease among children. It has a significant effect on patient's daily lives, as well as a big economic impact on society, as it affects 262 million people of the population globally. According to the previous research conducted in the Aseer region in southwestern Saudi Arabia, the prevalence rate of bronchial asthma was found to be 19.2%. Also, a number of studies revealed a significant prevalence of asthma in Saudi Arabia. Therefore, it is simple and effective to measure specific asthma symptoms among the adult population by utilizing the European Community Respiratory Health Survey (ECRHS) criteria. OBJECTIVES: To investigate asthma prevalence and measure asthma symptoms among Saudi adults in Qassim, Saudi Arabia using the ECRHS. METHODS: This cross-sectional study targets the males and females living in the Qassim region of Saudi Arabia. The study was conducted by handing out a validated, self-administered questionnaire among adult male and female patients in the Qassim region of Saudi Arabia. Both descriptive and inferential statistics analyses were conducted. To test the association, both chi-square and Fisher's exact tests were carried out. For the test, a p-value less than 0.05 was considered statistically significant. RESULTS: The study involved 461 participants who met the inclusion criteria. The study found that 137 (29.9%) participants reported having tightness in their chests when they woke up. Among the respondents who reported these symptoms were 83 (60.1%) female and 55 (39.9%) male respondents. This shows a statistically significant difference between the gender and severity of chest tightness upon waking up (p = 0.008) with more females experiencing it than the male gender. More so, there was a statistically significant difference between the gender and severity of shortness of breath (p = 0.008), with more females (81, 60.4%) having the symptoms than the male gender (53, 39.6%). In addition, the study results reveal statistically significant gender differences among the patients who were diagnosed with asthma by the physician (p = 0.003), with more males (51, 65.4%) having been diagnosed than the female gender (27, 34.6%). Asthma attacks in the 12 months (p = 0.047) and the use of tobacco products (p = 0.001) were also found to have a statistically significant difference across the genders. This was shown by most males (26, 65.0%) who had asthma attacks in the 12 months and 70 (98.6%) who smoked any tobacco products than the few females (14, 35.0%) who reported to have had asthma attacks in the 12 months and one (1.4%) who reported smoking any tobacco products. CONCLUSION: This study noted that the prevalence of asthma symptoms varied based on the gender of the participants. Therefore, the study suggests that gender should be taken as an important factor while evaluating the severity and how asthma-related symptoms manifest.

3.
ACS Mater Au ; 4(1): 74-81, 2024 Jan 10.
Article in English | MEDLINE | ID: mdl-38221925

ABSTRACT

Transition metal oxides are characterized by an acute structure and composition dependent electrocatalytic activity toward the oxygen evolution (OER) and oxygen reduction (ORR) reactions. For instance, Mn containing oxides are among the most active ORR catalysts, while Ni based compounds tend to show high activity toward the OER in alkaline solutions. In this study, we show that incorporation of Ni into α-MnO2, by adding Ni precursor into the Mn-containing hydrothermal solution, can generate distinctive sites with different electronic configurations and contrasting electrocatalytic activity. The structure and composition of the Ni modified hollandite α-MnO2 phase were investigated by X-ray absorption spectroscopy (XAS), X-ray diffraction (XRD), transmission electron microscopy coupled to energy-dispersive X-ray spectroscopy (TEM-EDX), inductively coupled plasma-optical emission spectroscopy (ICP-OES), and X-ray photoelectron spectroscopy (XPS). Our analysis suggests that Mn replacement by Ni into the α-MnO2 lattice (site A) occurs up to approximately 5% of the total Mn content, while further increasing Ni content promotes the nucleation of separate Ni phases (site B). XAS and XRD show that the introduction of sites A and B have a negligible effect on the overall Mn oxidation state and bonding characteristics, while very subtle changes in the XPS spectra appear to suggest changes in the electronic configuration upon Ni incorporation into the α-MnO2 lattice. On the other hand, changes in the electronic structure promoted by site A have a significant impact in the pseudocapacitive responses obtained by cyclic voltammetry in KOH solution at pH 13, revealing the appearance of Mn 3d orbitals at the energy (potential) range relevant to the ORR. The evolution of Mn 3d upon Ni replacement significantly increases the catalytic activity of α-MnO2 toward the ORR. Interestingly, the formation of segregated Ni phases (site B) leads to a decrease in the ORR activity while increasing the OER rate.

4.
Cureus ; 15(6): e40531, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37461772

ABSTRACT

Allergic bronchopulmonary aspergillosis (ABPA) is a condition characterized by an exaggerated response of the immune system (a hypersensitivity response) to the fungus Aspergillus. Aspergillus-associated pericarditis leading to pericardial tamponade is rare. In our case, we presented a case of a 22-year-old female asthmatic patient with no other medical conditions who presented to the emergency department (ED) complaining of severe chest tightness and shortness of breath. Echocardiography revealed significant pleural and pericardial effusion consistent with cardiac tamponade. Both pleural and pericardial fluids were hemorrhagic. Four months later, she presented to the ED with chief complaints of shortness of breath and a cough lasting two days. She was admitted as a case of asthma exacerbation. In the following months, when the patient visited the pulmonology outpatient clinic, the doctors recommended for specific IgE test. Allergen-specific IgE testing was positive for A. fumigatus to confirm the presence of ABPA. As we rolled out other causes of cardiac tamponade, we link the development of cardiac tamponade secondary to an underlying Aspergillus infection. We report this case with the aim of improving clinical knowledge regarding probable causes of cardiac tamponade in patients with asthma, which may facilitate the establishment of early diagnosis and treatment protocols.

5.
J Ethnopharmacol ; 312: 116492, 2023 Aug 10.
Article in English | MEDLINE | ID: mdl-37059248

ABSTRACT

ETHNOPHARMACOLOGICAL RELEVANCE: Artemisia sieberi Besser is a medicinal herb that has been traditionally used across the Middle East for the treatment of cancer. Further pharmacological studies on its extracts revealed that they possess cytotoxic activity against certain cancer cells, however, there were no studies conducted on the anticancer potential of Artemisia sieberi essential oil (ASEO). AIM OF THE STUDY: To evaluate the anticancer potential of ASEO, elucidate the oil's mode of action for the first time and investigate its chemical composition. MATERIALS AND METHODS: Artemisia sieberi was collected from Hail, Saudi Arabia, and its essential oil was obtained via hydrodistillation. The oil's activity against HCT116, HepG2, A549 and MCF-7 cells was assessed using SRB assay, while its anti-metastatic potential was assessed via a migration assay. Cell-cycle analysis and apoptosis assay were conducted via flow cytometry, while protein expression levels were investigated using Western blotting. The oil's chemical constituents were identified using GCMS. RESULTS: ASEO exerted its highest cytotoxic activity against MCF-7 with an IC50 value of 38.7 µg/ml. Further studies showed that the oil inhibited MCF-7 cells' migration, induced S-phase arrest and apoptosis. Western blot analysis showed no change in the expression level of caspase-3 after treatment, indicating the induction of caspase-independent apoptosis-like cell death in MCF-7. Treatment of MCF-7 with the oil resulted in downregulation of the protein expression levels of total ERK and its downstream target, LC3, indicating that any potential activation of the ERK signalling pathway during the cancer cells' growth would be inhibited. Finally, GCMS analysis identified the oil's major components as cis-crysanthenyl acetate (48.56%), davanone (10.28%), 1,8-cineole (6.81%) and caryophyllene diepoxide (5.34%), whereby it is suggested that these compounds might be responsible for the oil's bioactivity. CONCLUSION: ASEO possessed in vitro anticancer activity and modulated the ERK signalling pathway. This is the first study to explore the anticancer potential of ASEO in detail and reflects the significance of investigating essential oils from medicinal plants that have been traditionally used against cancer. This work might pave the way for further in vivo studies that could result in developing the oil into a natural effective anticancer treatment.


Subject(s)
Artemisia , Breast Neoplasms , Oils, Volatile , Plants, Medicinal , Humans , Female , Oils, Volatile/chemistry , Artemisia/chemistry , Down-Regulation , Breast Neoplasms/drug therapy , Apoptosis , Plants, Medicinal/metabolism , Caspases/metabolism
6.
Cureus ; 14(11): e31142, 2022 Nov.
Article in English | MEDLINE | ID: mdl-36505109

ABSTRACT

INTRODUCTION: Diabetic ketoacidosis (DKA) is a major complication affecting patients with diabetes. It is often the first presentation of type I diabetes and can also occur due to a lack of compliance with insulin therapy or infection, among other causes. Hospitalizations for DKA have increased globally among patients with type I and type II diabetes, which poses a strain on health systems. AIM: To determine the factors impacting the time to resolution of metabolic parameters in DKA patients. METHODS: This retrospective study was performed by reviewing the clinical records of hospitalized DKA patients at King Fahad Specialist Hospital, a tertiary-level healthcare center in Buraidah, Al Qassim region, Saudi Arabia. The study included all DKA admissions that met the inclusion criteria between September 2019 and April 2022. RESULTS: A total of 129 patients with a diagnosis of DKA from January 2019 to April 2022 were identified. Of these, 67 patients met the inclusion criteria. More females experienced DKA (56.7%), and the study population had an improvement rate of 97%. The mean length of stay (LOS) for patients with DKA was 73.19 hours, and the median time for DKA resolution was 15 hours (mean time 21.38 hours). The omission of insulin was the leading precipitating factor for DKA (43%) followed by infection (12%). A high serum bicarbonate (HCO3) level was identified as an independent predictor for a longer time to resolution. Patients with DKA who have high glucose levels on admission, higher body mass index (BMI), older age, and higher weight stayed in the hospital for extended periods. Conversely, patients with a higher serum potential of Hydrogen (pH) had a shorter LOS. Age was the only clinically independent predictor for a minimum LOS for DKA. Patients with comorbidities had a longer hospital LOS than patients without comorbidities; no such relationship has been reported in other studies. Patients in our study population had a longer time of resolution than observed in other studies, although no clear cause was identified. CONCLUSION: This study contributes to our understanding of DKA in hospitalized patients in Saudi Arabia. This is the first study to link patients with DKA who have comorbidities to a longer hospital stay in the kingdom of Saudi Arabia. This study also identified multiple clinical and biochemical parameters related to the variability in LOS and time to resolution of DKA in hospitalized patients.

7.
Gen Physiol Biophys ; 41(4): 309-318, 2022 Jul.
Article in English | MEDLINE | ID: mdl-35938964

ABSTRACT

Selenium enhances the cellular antioxidant capacity and alleviates oxidative stress. We investigated the transcriptional and enzymatic activities of selenium-dependent glutathione peroxidase 1 and thioredoxin reductase 1 (TrxR1), and levels of glutathione, hydrogen peroxide, lipid peroxides, and protein carbonyls in primary passage 5 (P5) and senescent passage 25 (P25) and 30 (P30) fibroblasts. Cells were incubated in either standard Dulbecco growth medium (CM1) containing normal plasma selenium levels (0.8 µmol/l), or in CM2, CM3, and CM4 containing 3 µmol/l (5 µmol/l for TrxR1) sodium selenite, L-hydroxyselenomethionine, or Se-methylselenocysteine, respectively. Gene transcripts and activities of both investigated enzymes as well as the levels of reduced glutathione were significantly increased in CM2-, CM3-, and CM4-incubated senescent P25 and P35 cells compared against those incubated in CM1. In congruence, although all oxidative stress parameters including oxidized glutathione were significantly lower in CM2-, CM3-, and CM4-incubated senescent cells compared against those incubated in CM1, such reductions were of significantly higher magnitude in CM3 and CM4 cells compared against those in CM2. In conclusion, organic L-hydroxyselenomethionine and Se-methylselenocysteine are equally more potent at alleviating oxidative stress in senescent cells than inorganic sodium selenite, and thus could be beneficial for use in elderly subjects and those with oxidative stress-associated disease.


Subject(s)
Selenium , Aged , Antioxidants/metabolism , Fibroblasts , Glutathione/metabolism , Glutathione Peroxidase/genetics , Glutathione Peroxidase/metabolism , Humans , Oxidative Stress , Selenium/pharmacology , Sodium Selenite/pharmacology , Thioredoxin Reductase 1/metabolism
8.
Adv Virol ; 2022: 9240941, 2022.
Article in English | MEDLINE | ID: mdl-35812166

ABSTRACT

COVID-19 is a disease caused by a novel coronavirus with no specific, standard treatment. We investigated the clinical data of COVID-19 patients admitted to King Fahad Specialist Hospital (KFSH) in Buraydah by comparing the patients who were treated early with favipiravir (within 3 days of admission) to patients who were treated after three days of admission or not treated. 165 patients were confirmed with PCR tests and admitted to KFSH for treatment. Comorbidities contributed significantly to increasing the length of stay in hospital at 11.4 ± 0.8 days compared to patients with no comorbidities at 8.6 ± 0.9 days (p=0.041). A total of 103 patients were treated with favipiravir, and we found that early treatment with favipiravir (within 3 days) reduced the length of stay in hospital significantly (8.8 ± 1.4 days) compared to patients who were treated after 3 days (13.3 ± 4.6 days) (p=0.0015). Moreover, patients with comorbidities in both early and late treatment groups had significantly higher average lengths of stay in hospital (11.2 ± 0.9 days) compared to patients with no comorbidities (7.9 ± 0.7 days) (p=0.017). Interestingly, patients treated early with favipiravir (with comorbidities and without) stayed fewer days in hospital compared to those with late treatment (p=0.021; a difference of 4.5 ± 1.9 days; and p=0.018; a difference of 4.2 ± 1.7 days, respectively). In conclusion, our analysis indicates that early treatment with favipiravir can reduce the length of stay in hospital and improve clinical manifestations of COVID-19 patients.

9.
Korean J Physiol Pharmacol ; 26(4): 263-275, 2022 Jul 01.
Article in English | MEDLINE | ID: mdl-35766004

ABSTRACT

There is a paucity of detailed data related to the effect of senescence on the mitochondrial antioxidant capacity and redox state of senescent human cells. Activities of TCA cycle enzymes, respiratory chain complexes, hydrogen peroxide (H2O2), superoxide anions (SA), lipid peroxides (LPO), protein carbonyl content (PCC), thioredoxin reductase 2 (TrxR2), superoxide dismutase 2 (SOD2), glutathione peroxidase 1 (GPx1), glutathione reductase (GR), reduced glutathione (GSH), and oxidized glutathione (GSSG), along with levels of nicotinamide cofactors and ATP content were measured in young and senescent human foreskin fibroblasts. Primary and senescent cultures were biochemically identified by monitoring the augmented cellular activities of key glycolytic enzymes including phosphofructokinase, lactate dehydrogenase, and glycogen phosphorylase, and accumulation of H2O2, SA, LPO, PCC, and GSSG. Citrate synthase, aconitase, α-ketoglutarate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, isocitrate dehydrogenase, and complex I-III, IIIII, and IV activities were significantly diminished in P25 and P35 cells compared to P5 cells. This was accompanied by significant accumulation of mitochondrial H2O2, SA, LPO, and PCC, along with increased transcriptional and enzymatic activities of TrxR2, SOD2, GPx1, and GR. Notably, the GSH/GSSG ratio was significantly reduced whereas NAD+/NADH and NADP+/NADPH ratios were significantly elevated. Metabolic exhaustion was also evident in senescent cells underscored by the severely diminished ATP/ADP ratio. Profound oxidative stress may contribute, at least in part, to senescence pointing at a potential protective role of antioxidants in aging-associated disease.

10.
J Family Med Prim Care ; 11(3): 896-903, 2022 Mar.
Article in English | MEDLINE | ID: mdl-35495807

ABSTRACT

Background: The coronavirus disease-2019 (COVID-19) is a global public health disaster imposing a nationwide lockdown. This study was undertaken to determine the impact of COVID-19 quarantine on physical, nutritional, psychosocial life, and work aspects on the population of Saudi Arabia. Methods: Data collection was based on the fear of COVID-19 Scale (FCV-19S) and was analyzed by the Likert-type scale. A total of 2828 individuals participated during their COVID-19 quarantine. The data were collected during June 10-17, 2020 using the psychosocial FCV-19S. Results: COVID-19 quarantine was negatively correlated with the physical, nutritional, psychosocial life and work aspects of the Saudi Arabia's population (P < 0.05). As a result of the correlation analysis, gender, sociodemographic status and having a family member dying of COVID-19, marital status (single), monthly income (<3000) and occupation (student), and lost a job or businesses were significantly associated with fear of COVID-19 (P < 0.05). Furthermore, the participants reported a reduction in their physical activity by 59%, whereas 26.5% of participants showed an increase of body weight. Moreover, 23% of participants lost their jobs during the pandemic. Conclusions: The lockdown period was associated with an increase in the COVID-19 fear score. The degree FCV-19S was varied in different categories in several aspects. Low levels of physical activity and weight gained were observed during the lockdown period.

11.
PLoS One ; 16(12): e0260259, 2021.
Article in English | MEDLINE | ID: mdl-34879074

ABSTRACT

BACKGROUND: After recovery from acute infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), many patients experience long-term symptoms in different body systems. The aim of the present study was to identify these symptoms, their severity, and their duration as a first step in building a system to classify post-recovery long-term symptoms of coronavirus disease 2019 (COVID-19). METHODS: An online-based cross-sectional survey was administered between September and October 2020. Data regarding the severity of post-recovery symptoms and their duration were collected using an Arabic questionnaire divided into six categories encompassing the 20 most prevalent symptoms. RESULTS: A total of 979 patients recovered from COVID-19 in Saudi Arabia in the study period, of whom 53% were male and 47% were female. The most common symptoms included general fatigue and weakness (73% each), with moderate severity of neurological symptoms including mood changes (41%) and insomnia (39%). Among the special senses, loss of smell and taste of marked severity were reported by 64% and 55% among respiratory symptoms, cough of mild severity (47%), and dyspnea of moderate severity (43%). Loss of appetite of moderate severity was reported in 42%, and diarrhea, abdominal pain, and nausea of mild severity were reported by 53%, 50%, and 44% of respondents, respectively. CONCLUSIONS: Long-term symptoms after recovery from COVID-19 warrant patient follow-up. The authors propose a classification system as a starting point to guide the identification and follow-up of long-term symptoms post-recovery, and recommend larger-scale studies to broaden the definition of recovery from COVID-19, which appears to have two phases, acute and chronic.


Subject(s)
COVID-19/pathology , Adolescent , Adult , Aged , Aged, 80 and over , COVID-19/complications , COVID-19/epidemiology , COVID-19/virology , Child , Cough/etiology , Cross-Sectional Studies , Fatigue/etiology , Female , Humans , Male , Middle Aged , Mood Disorders/etiology , SARS-CoV-2/isolation & purification , Saudi Arabia/epidemiology , Severity of Illness Index , Sleep Initiation and Maintenance Disorders/etiology , Surveys and Questionnaires , Young Adult
12.
J Nurs Manag ; 26(4): 485-492, 2018 May.
Article in English | MEDLINE | ID: mdl-29214716

ABSTRACT

AIM: To assess the psychometric properties of the Spiritual Climate Scale Arabic version for Saudi nurses. BACKGROUND: Evidence showed that a high level of spiritual climate in the workplace is associated with increased productivity and performance, enhanced emotional intelligence, organisational commitment and job satisfaction among nurses. METHOD: A convenient sample of 165 Saudi nurses was surveyed in this descriptive, cross-sectional study. Cronbach's α and intraclass correlation coefficient of the 2 week test-retest scores were computed to establish reliability. Exploratory factor analysis was performed to support the validity of the Spiritual Climate Scale Arabic version. RESULTS: The Spiritual Climate Scale Arabic version manifested excellent content validity. Exploratory factor analysis supported a single factor with an explained variance of 73.2%. The Cronbach's α values of the scale ranged from .79 to .88, while the intraclass correlation coefficient value was .90. The perceived spiritual climate was associated with the respondents' hospital, gender, age and years of experience. CONCLUSIONS: Findings of this study support the sound psychometric properties of the Spiritual Climate Scale Arabic version. IMPLICATIONS FOR NURSING MANAGEMENT: The Spiritual Climate Scale Arabic version can be used by nurse managers to assess the nurses' perception of the spiritual climate in any clinical area. This process can lead to spiritually centred interventions, thereby ensuring a clinical climate that accepts and respects different spiritual beliefs and practices.


Subject(s)
Nursing Staff, Hospital/psychology , Spirituality , Surveys and Questionnaires , Adult , Cross-Sectional Studies , Female , Humans , Male , Nursing Staff, Hospital/organization & administration , Nursing Staff, Hospital/statistics & numerical data , Organizational Culture , Psychometrics , Reproducibility of Results , Saudi Arabia , Translations
13.
J Environ Radioact ; 144: 69-76, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25827573

ABSTRACT

Radon and thoron are radioactive gases that can emanate from soil and building materials, and it can accumulate in indoor environments. The concentrations of radon and thoron in the air from various workplace categories in Brisbane, Australia were measured using an active method. The average radon and thoron concentrations for all workplace categories were 10.5 ± 11.3 and 8.2 ± 1.4 Bq m(-3), respectively. The highest radon concentration was detected in a confined area, 86.6 ± 6.0 Bq m(-3), while the maximum thoron level was found in a storage room, 78.1 ± 14.0 Bq m(-3). At each site, the concentrations of radon and thoron were measured at two heights, 5 cm and 120 cm above the floor. The effect of the measurement heights on the concentration level was significant in the case of thoron. The monitoring of radon and thoron concentrations showed a lower radon concentration during work hours than at other times of the day. This can be attributed to the ventilation systems, including the air conditioner and natural ventilation, which normally operate during work hours. The diurnal variation was less observed in the case of thoron, as the change in its concentration during and after the working hours was insignificant. The study also investigated the influence of the floor level and flooring type on indoor radon and thoron concentrations. The elevated levels of radon and thoron were largely found in basements and ground floor levels and in rooms with concrete flooring.


Subject(s)
Air Pollutants, Radioactive/analysis , Air Pollution, Indoor/analysis , Occupational Exposure , Radiation Monitoring , Radon/analysis , Universities , Queensland , Radon Daughters/analysis , Workplace
14.
J Environ Radioact ; 129: 94-9, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24412530

ABSTRACT

The measurement of radon ((222)Rn) activity flux using activated charcoal canisters was examined to investigate the distribution of the adsorbed (222)Rn in the charcoal bed and the relationship between (222)Rn activity flux and exposure time. The activity flux of (222)Rn from five sources of varying strengths was measured for exposure times of one, two, three, five, seven, 10, and 14 days. The distribution of the adsorbed (222)Rn in the charcoal bed was obtained by dividing the bed into six layers and counting each layer separately after the exposure. (222)Rn activity decreased in the layers that were away from the exposed surface. Nevertheless, the results demonstrated that only a small correction might be required in the actual application of charcoal canisters for activity flux measurement, where calibration standards were often prepared by the uniform mixing of radium ((226)Ra) in the matrix. This was because the diffusion of (222)Rn in the charcoal bed and the detection efficiency as a function of the charcoal depth tended to counterbalance each other. The influence of exposure time on the measured (222)Rn activity flux was observed in two situations of the canister exposure layout: (a) canister sealed to an open bed of the material and (b) canister sealed over a jar containing the material. The measured (222)Rn activity flux decreased as the exposure time increased. The change in the former situation was significant with an exponential decrease as the exposure time increased. In the latter case, lesser reduction was noticed in the observed activity flux with respect to exposure time. This reduction might have been related to certain factors, such as absorption site saturation or the back diffusion of (222)Rn gas occurring at the canister-soil interface.


Subject(s)
Air Pollutants, Radioactive/analysis , Charcoal/chemistry , Radiation Monitoring/methods , Radon/analysis , Adsorption , Air Pollutants, Radioactive/chemistry , Radiation Monitoring/instrumentation , Radon/chemistry , Time Factors
SELECTION OF CITATIONS
SEARCH DETAIL
...